''Druon quercuslanigerum'' is a species of

gall wasp Gall wasps, also traditionally called gallflies, are hymenopterans of the family Cynipidae in the wasp superfamily Cynipoidea. Their common name comes from the galls they induce on plants for larval development. About 1,300 species of this gene ...

that forms

galls Galls (from the Latin , 'oak-apple') or ''cecidia'' (from the Greek , anything gushing out) are a kind of swelling growth on the external tissues of plants. Plant galls are abnormal outgrowths of plant tissues, similar to benign tumors or wart ...

on ''

Quercus virginiana ''Quercus virginiana'', also known as the southern live oak, is an evergreen oak tree endemic to the Southeastern United States. Though many other species are loosely called live oak, the southern live oak is particularly iconic of the Old South. ...

'', ''

Quercus geminata ''Quercus geminata'', commonly called sand live oak, is an evergreen oak tree native to the coastal regions of the subtropical southeastern United States, along the Atlantic Coast from southern Florida northward to southeastern Virginia and al ...

'', ''

Quercus fusiformis ''Quercus fusiformis'' (also often referred to as ''Q. virginiana'' var. ''fusiformis''), commonly known as escarpment live oak, plateau live oak, plateau oak, or Texas live oak, is an evergreen or nearly evergreen tree. Its native range inc ...

'', and ''

Quercus oleoides ''Quercus oleoides'', with Spanish common names encina or encino, is a Mesoamerican species of oak in the southern live oaks section of the genus ''Quercus'' ( section ''Virentes''). It grows in dry forests and pastureland of eastern and souther ...

''. There are both asexual and sexual generations. The asexual generation forms galls on the leaves whereas the sexual generation forms galls on the

catkin A catkin or ament is a slim, cylindrical flower cluster (a spike), with inconspicuous or no petals, usually wind- pollinated ( anemophilous) but sometimes insect-pollinated (as in '' Salix''). It contains many, usually unisexual flowers, arra ...

s. It can be found in the southern

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

and

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

. Predators of this species include the

green parakeet The green parakeet (''Psittacara holochlorus''), green conure, or Mexican green conure is a New World parrot. As defined by the International Ornithological Committee (IOC), it is native to Mexico and southern Texas in the Rio Grande Valley. Ta ...

Taxonomy

''Druon quercuslanigerum'' was first described in 1881 by

William Harris Ashmead William Harris Ashmead was an American entomologist born on 19 September 1855 at Philadelphia. He died 17 October 1908 at Washington D.C. After his studies in Philadelphia, Ashmead worked for the publisher J. B. Lippincott & Co. Later, he settled ...

, as part of the genus '' Cynips'', but moved the species to the genus ''

Andricus ''Andricus'' is a genus of oak gall wasps in the family (biology), family Cynipidae. Life cycle As in all Hymenoptera, sex-determination system, sex-determination in species of the genus ''Andricus'' is governed by haplodiploidy: males develop f ...

'' four years later. In 2022, it was moved to the re-established genus '' Druon''.

Description

The asexual generation gall consists of an inner capsule of mature galls with a woolly covering, typically appearing on the underside of leaves along the mid-vein. A mature gall measures 1.0–7.0 mm in diameter and 2–3 mm high. The woolly covering varies from creamy white to yellowish-white when older, and the inner capsule is light brown. The galls can appear singly or in clusters of three to six galls. The sexual generation galls form on catkins in the spring. They appear as a small (~1 mm) ovate swelling of the central stem of the catkin. The asexual generation female is reddish-brown and measures 2-2.5 mm, while the smaller sexual female is dark-red brown to black and measures 1.4–2.1 mm in length. The sexual generation male, similar in coloration to the female, measures 1.2–1.6 mm in length.

Life history

Upon emerging from catkin galls in mid-March to early April, the sexual generation mates and lays eggs in the mid-rib of new leaves. The woolly galls develop from mid to late summer through the fall and winter, with asexual females emerging from September through February. This emergence period coincides with catkin bud production, where the asexual females lay their eggs. The emergence period of the asexual generation is approximately ten times longer than that of the sexual generation.

Gallery

Druon quercuslanigerum asexual generation.jpg, ''Druon quercuslanigerum'' asexual female Druon quercuslanigerum Sexual Generation Female.jpg, ''Druon quercuslanigerum'' sexual female Druon quercuslanigerum sexual female ovipositing.jpg , ''Druon quercuslanigerum'' sexual female ovipositing into a leaf mid-rib

References

{{Taxonbar, from=Q113156500 Hymenoptera of North America Gall-inducing insects Cynipidae Oak galls Insects described in 1881 Taxa named by William Harris Ashmead